An image processor is known from Japanese Kokai Patent Application No. 2004-220059. With this known image processor, the optical flow at each point is calculated from the image, the optical flows are grouped into multiple regions, and the background and independent moving objects are detected based on the optical flow information for each region.
In this conventional device, optical flow is calculated and processing is performed for the entire image to detect the background and moving objects. Because there are many differences in the background and objects that appear based upon their position in the image, the problem produced is that errors can occur when the same processing is executed for the entire image to detect the background and moving objects.